An acoustic guitar is generally seen as a refined musical instrument comprised generally of a neck connected at an end of a sound box to generally support a set of strings, the guitar being designed to substantially release the kinetic energy transmitted by strings during operation to transform some of that energy into audible, controllable sound. To accomplish this capability, the strings may be placed into adjustable tension in parallel orientation across a sound hole generally located on the top of the soundboard by a nut (e.g., a grooved member placed laterally across the neck at its end) and a saddle/bridge combination (e.g., at the sound box end) to lift the strings up and away in a parallel manner from the top of the sound box. When plucked, the musical strings may produce a sustaining signal of vibration-based pulses that may be transmitted to the guitar's soundboard and neck by the nut, saddle, and bridge. Only a small fraction of the string's energy leaves directly as sound. The pulses sent into the soundboard cause a complex vibration of the sound box's structure to create most of audible tones for the guitar during playing while a series of rapid pressure fluctuations occurring at the sound hole creates a smaller set of audible signals.
During the playing of the guitar, the striking or plucking of the strings may be accomplished by direct string contact, generally over the sound hole, with the players' finger tips or a plectrum (e.g., pick) held in the player's fingers. Because of the close proximity of the strings to the soundboard and sound hole, while the player is generally strumming (moving one of its hands up and down over the strings), the player may contact the lower edges of the sound hole with its fingers or the pick while striking the strings in a downward motion. The material (e.g., wood and any protective treatment) composing the top of the sound box and a lower portion of the sound hole edge (as well as that area directly located below the sound hole) may be susceptible to damage due to this contact (especially from the pick contact or strike). Even when the guitar is just moderately played, such pick contact may damage the sound hole edge and it's surrounding area on the soundboard. Some of the damage that may occur include, but are not limited to; the marring/scratching of lacquer/resin finish of the guitar; exposing bare wood; chipping of wood (which may further result to cracking extending downward onto the soundboard) and the like. This damage may not only effect the resonance capability of the sound box (leading to the degradation of sound emissions) but may so serious impair or weaken the structure of the top of the sound box as to effectively prevent the playing of the guitar, thus leading to the guitar's replacement (which could cost several thousands of dollars).
There have been some attempts to limit such damage, but most these attempts appear to focus not on sound hole damage but rather soundboard top surface damage from pick contact. One such attempt could be a pick guard, generally seen as a plate or sheet of thin acrylic plastic or the like that is permanently applied to the top of the sound box proximate along the lower region of the sound hole. Although it may be applied post manufacture by guitar owners and users, guitar makers have also been applying the pick guard during guitar construction. Some limitations of this protection may occur, depending upon the manufacture of the guitar, wherein the pick guard placement on the guitar leaves an unprotected gap running concentric to the sound hole between the sound hole edge and the top of the pick guard.
What could be needed is a dedicated sound hole guard that can be applied during or post guitar manufacture that helps ameliorate or prevent the damage that can occur with pick-to-sound hole contact without substantially affecting the sound performance of the guitar. This guard could be definite length of resilient polymer, metal, or other mar resistant material substantially having at least an L-shaped or a U-shaped lateral cross section with an overall lunar shape (or could be bent to accommodate a curvature of a portion edge of the soundboard denoting the sound hole) wherein the guard is applied over the lower sound hole edge that denotes sound hole so that at least a portion of the edge is retained within the guard. Such a guard could be used to stabilize and possibly strengthen the soundboard top area that suffers pick strike damage to the extent of possibly restoring such damaged guitars to playing condition.